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    <title>Document</title>
    <script>
        //根据位置返回字符
        //1.chatAt(index) 根据位置返回字符
        var str='andy';
        console.log(str.charAt(3));
        //遍历所有的字符
        for(var i=0;i<str.length;i++){
            console.log(str.charAt(i));
        }
        //2.charCodeAt(index)返回相应索引号的字符ASCII值 目的: 判断用户按下了那个键
        console.log(str.charCodeAt(0));//97
        //3.str[index] h5新增的
        console.log(str[0]);
    </script>
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